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The primary cause of bottled wine sediment is tartrate crystal precipitation. To prevent this, wines undergo a stabilization process before bottling. The most commonly used method is cold stabilization, which induces the precipitation of tartrate crystals that are then removed, thereby eliminating the excess ions that cause instability in wine. Another approach to tartaric stabilization is using enological stabilizers with a colloid protective effect, which prevents the formation of tartrate crystals. The most commonly used tartaric stabilizers are sodium carboxymethylcellulose (CMC) and metatartaric acid. However, both have drawbacks: they are semi-synthetic products, and metatartaric acid degrades over time, losing its stabilizing effect. This study aims to compare the effects of cold stabilization, stabilization with CMC, and metatartaric acid on the chemical composition, particularly the volatilome, of white, rosé, and red wines. Cold stabilization significantly impacted the wine volatilome, especially in white and rosé wines, by decreasing total alcohols and increasing total esters. It also reduced the color intensity of rosé and red wines by lowering monomeric anthocyanins. In contrast, enological stabilizers had minimal impact on the wines' phenolic composition, chromatic characteristics, and volatilome. The sensory impact of cold stabilization is complex; it can potentially enhance the aroma of white and rosé wines by increasing ester VOCs and decreasing higher alcohols, but it negatively affects the color of rosé and red wines. [ABSTRACT FROM AUTHOR]

Previous research has suggested that the impact of smoke affected wines require human evaluation due to in‐mouth changes in perception, perhaps associated with saliva. Smoke affected wines (n = 36) from three major wine growing regions in the US were sourced from commercial wineries. A subset of these wines (n = 7) were evaluated by a consumer panel (n = 57) and electronic tongue (e‐tongue) to determine the influence of saliva in the sensory profile. Consumers assessed the wines for aroma and other sensory attributes, before and after individual saliva addition. Pooled saliva from consumers was used to treat all wines obtained (n = 36) and then analyzed using the e‐tongue. Results showed that saliva did not significantly alter the overall aroma, other than fruity or woody aroma liking by consumers (p >.05). However, the presence of saliva significantly lowered overall liking in both red and white wines that were affected by smoke (p ≤.05). Consumers rated the subset of smoke affected wines below the "might purchase" category, indicating these wines were not considered acceptable by consumers. When individual pairs of smoke affected wines (before and after saliva additions) were assessed using the e‐tongue, the device was able to differentiate the pairs, validating potential usefulness to discern wine changes, though the discrimination indices were moderate to low (68.8% to 11.9%). Based on these data, in human ratings of the aroma and appearance of smoked affected wines, saliva decreased overall liking, and this was somewhat distinguishable by e‐tongue analysis. [ABSTRACT FROM AUTHOR]

Real-time monitoring of microbial dynamics during fermentation is essential for wine quality control. This study developed a method that combines the fluorescent dye propidium monoazide (PMA) with CELL-qPCR, which can distinguish between dead and live microbes for Lactiplantibacillus plantarum. This method could detect the quantity of microbes efficiently and rapidly without DNA extraction during wine fermentation. The results showed that (1) the PMACELL-qPCR enumeration method developed for L. plantarum was optimized for PMA treatment concentration, PMA detection sensitivity and multiple conditions of sample pretreatment in wine environment, and the optimized method can accurately quantify 104-108 CFU/mL of the target strain (L. plantarum) in multiple matrices; (2) when the concentration of dead bacteria in the system is 104 times higher than the concentration of live bacteria, there is an error of 0.5-1 lg CFU/mL in the detection results. The optimized sample pretreatment method in wine can effectively reduce the inhibitory components in the qPCR reaction system; (3) the optimized PMA-CELL-qPCR method was used to monitor the dynamic changes of L. plantarum during the fermentation of Cabernet Sauvignon wine, and the results were consistent with the plate counting method. In conclusion, the live bacteria quantification method developed in this study for PMA-CELLqPCR in L. plantarum wines is accurate in quantification and simple in operation, and can be used as a means to accurately monitor microbial dynamics in wine and other fruit wines. [ABSTRACT FROM AUTHOR]

The Bohai Bay region is a famous wine-growing area in China, where the rainfall is concentrated in the summer due to the influence of the temperate semi-humid monsoon climate. As such, the vineyard terrain has a significant impact on the flavor quality of the grapes and the resulting wines. To explore the relationship between the 'Cabernet Sauvignon' wine style and terrain, this study takes four different plots in the Jieshi Mountain region to investigate the differences in the aroma profile of Cabernet Sauvignon grapes and wines of two consecutive vintages. Based on two-way ANOVA, there were 25 free and 8 glycosylated aroma compounds in the grapes and 21 and 10 aroma compounds with an odor activity value greater than 0.1 in the wines at the end of alcohol fermentation (AF) and malolactic fermentation (MLF), respectively, that varied among the four plots. Wines from the four plots showed a significant difference in floral and fruity aroma attributes, which were mainly related to esters with high odor activity values. The difference in concentration of these compounds between plots was more pronounced in 2021 than in 2020, and a similar result was shown on the Shannon–Wiener index, which represents wine aroma diversity. It has been suggested that high rainfall makes the plot effect more pronounced. Pearson's correlation analysis indicated that concentrations of (E)-3-hexen-1-ol in grapes and ethyl 3-methylbutanoate, ethyl hexanoate, isoamyl acetate, isopentanoic acid, and phenethyl acetate in wines were strongly positively correlated with the concentrations of N, P, K, Fe, and electrical conductivity in soil but negatively correlated with soil pH. This study laid a theoretical foundation for further improving the level of vineyard management and grape and wine quality in the Jieshi Mountain region. [ABSTRACT FROM AUTHOR]

For oenological products, most of the intrinsic and extrinsic drivers of perceived quality are associated with specific aromatic profiles. Aromatic diversity has been recognized as a central element in perceived quality as it is able to transmit the complex interactions between grape variety, geographical characteristics, and viticultural and winemaking practices, including the fermentative process. A comprehensive characterization of flavour compounds by headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to mass spectrometric analysis is often needed in order to ascertain the quality of wine. HS-SPME requires a proper optimization that can be achieved through an adequate experimental design. Here, a HS-SPME/GC-MS based method was developed to investigate the volatile compounds of wine samples obtained by laboratory-scale fermentations. This was performed by inoculating a commercial Saccharomyces cerevisiae strain, which is used both as single starter and as mixed starter, with an indigenous Hanseniaspora osmophila strain. The experimental conditions of HS-SPME (extraction temperature and time) were optimized by applying a face-centred composite experimental design. Up to 95% of the total variance was explained by the proposed model. The optimized method allowed us to confirm the usefulness of combining the inoculation of grapes with selected yeast strains in co-culture situations in order to improve the wine bouquet. [ABSTRACT FROM AUTHOR]

Globally, the red wine market experienced a rapid growth in the last decade, due to the superior colour, taste, and nutritional quality. The red grapes used for vinification have individual characteristics varying within the regional environment. In this study, the quality of seven grape cultivars, including Marselan, Yan 73, Muscat Hamburg, Kadarka, Merlot, Cabernet Sauvignon, and Crimpose, and their corresponding wines, were investigated based on high-performance liquid chromatography and headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry. These techniques were performed to analyze the chemical compositions and volatile compounds of the tested samples, respectively. The results showed that tartaric acid (29.96% to 73.45%) and rutin (12.53% to 56.54%) were the dominant organic acid and phenolic compounds in grapes, respectively. Higher concentrations of organic acids and phenolic compounds, and the types of volatile compounds, were observed to be highest in the Cabernet Sauvignon grape. The antioxidant activity of wines ranged from 6.74 to 102.68 mmol TE/L, and Yan 73 wine had the highest antioxidant activity. A total of 69 volatile compounds consisting of 17 alcohols, 26 esters, 5 aldehydes, 9 acids, 7 ketones, and 5 other volatile compounds were identified in all tested wines, and 11 important aroma active substances (odor activity value > 1) were selected, consisting of β-ionone, phenethyl acetate, geranyl acetate, ethyl 9-decenoate, ethyl caprate, ethyl pelargonate, decanal, ethyl caprylate, 6-methyl-5-hepten-2-one, methyl 2-hexenoate, and ethyl hexanoate, which endow wines with a unique aroma. This work clearly describes the chemical and sensory characteristics of seven red grape cultivars in Xinjiang of China and provides diversity options for cultivars for winemaking. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the influence of caffeic and caftaric acid, fructose, and storage temperature on the formation of furan-derived compounds during storage of base wines. Base wines produced from Chardonnay grapes were stored at 15 and 30 °C for 90 days with additions of fructose, caffeic acid, and caftaric acid independently or in combinations. Wines were analyzed following 90 days of storage for: total hydroxycinnamic acids, degree of browning, caffeic acid and caftaric acid concentrations, and nine furan-derived compounds. Caffeic and caftaric acid additions increased homofuraneol concentration by 31% and 39%, respectively, at 15 °C (p < 0.05). Only the addition of caffeic acid increased furfural by 15% at 15 °C (p < 0.05). Results demonstrate that some furan derivatives over 90 days at 15 °C increased slightly with 5 mg/L additions of caffeic and caftaric acid. This is the first time the influence of hydroxycinnamic acids on furan-derived compounds has been reported during short-term aging of base wine at cellar temperature. [ABSTRACT FROM AUTHOR]

Twenty-five samples of different Slovak wines before and after filtration were analysed in order to determine the content of eight biogenic amines (tryptamine, phenylalanine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine). The method involves extraction of biogenic amines from wine samples with used dansyl chloride. Ultra-high performance liquid chromatography (UHPLC) was used for determination of biogenic amines equipped with a Rapid Resolution High Definition (RRHD), DAD detectors and Extend-C18 LC column (50 mm x 3.0 mm ID, 1.8 ?m particle size). In this study the highest level of biogenic amine in all wine samples represent tryptamine (TRM) with the highest content 170.9?5.3 mg/L in Pinot Blanc wine. Phenylalanine (PHE) cadaverine (CAD), histamine (HIS) and spermidine (SPD) were not detected in all wines; mainly SPD was not detected in 16 wines, HIS not detected in 14 wines, PHE and CAD not detected in 2 wines. Tyramine (TYR), spermine (SPN) and putrescine (PUT) were detected in all wines, but PUT and SPN in very low concentration. The worst wine samples with high biogenic amine content were Saint Laurent (BF), Pinot Blanc (S) and Pinot Noir (AF). [ABSTRACT FROM AUTHOR]

The influence of the two technological parameters, temperature (20 °C, 24 °C, 28 °C) and the inoculum amount of the yeast culture (2%, 3%, 4%) on the duration of the alcoholic fermentation and the ester-producing capacity of the Badachoni and the 24-6 strains of Saccharomyces cerevisiae species was studied. The yeast exhibited high fermentation activity. The intensity with which it initiated the process and the time for its completion was in correlation with the studied factors. The strains showed the best activity at 28 °C/4%. Neural networks were applied and mathematical models were derived, properly describing the fermentation process and the change in the total amount of esters in the course of the process, depending on the technological conditions. The rate in the dynamic of the esters during the process was monitored in 4 stages - onset, rapid fermentation, quiet fermentation, and after malolactic fermentation. The maximum quantity of esters was synthesized in the middle of the process. During alcoholic fermentation, the esters followed a tendency to increase with decreasing the temperature, increasing the amount of yeast culture and the time of the process. The Badachoni and the 24-6 strains demonstrated the highest ester-producing capacity under the temperature of 20 °C and with the 4% inoculum of the yeast culture. The Badachoni strain quantitatively produced more esters than the 24-6 strain. No strict correlation was found between the amount of esters and the organoleptic properties of the wines. The sample containing the most esters had the highest tasting score only in the variants of the 24-6 strain. [ABSTRACT FROM AUTHOR]

This review takes a snapshot of the main multivariate statistical techniques and methods used to process data on the concentrations of wine volatile molecules extracted by means of solid phase micro-extraction and analyzed using GC-MS. Hypothesis test, exploratory analysis, regression models, and unsupervised and supervised pattern recognition methods are illustrated and discussed. Several applications in the wine volatolomic sector are described to highlight different interactions among the various matrix components and volatiles. In addition, the use of Artificial Intelligence-based methods is discussed as an innovative class of methods for validating wine varietal authenticity and geographical traceability. [ABSTRACT FROM AUTHOR]

An improved method for the simultaneous determination of seven biogenic amines is described by high-performance liquid chromatography (HPLC). The targeted compounds were diluted and extracted with 0.1 M HCl. The isolated biogenic amines were derivatized with dansyl chloride using optimized conditions followed by separation and analysis using a developed and validated HPLC method with diode-array detection. Eighteen samples from four traditional wines (Toddy, Mijiu, Uangjiu, and Huangjiu) produced in Malaysia were analyzed for their biogenic amine contents. The results showed that histamine and tryptamine were the most prevalent biogenic amines, followed by cadaverine, phenylethylamine, putrescine, spermidine, and tyramine. Histamine and cadaverine were detected at high levels in the Toddy samples, while histamine and trytamine were commonly present in the Mijiu, Uangjiu, and Huangjiu products. The total biogenic amines ranged from undetected to 465.4 ± 7.6 mg/L. All of the analyzed samples contained tyramine below the threshold of 10 mg/L, while 16.7% had histamine levels higher than the limit of 20 mg/L. The wines with high histamine contents may possibly be a risk to human health. [ABSTRACT FROM AUTHOR]

The relationship between wine polyphenols and health has been receiving growing scientific attention in the last few years. To confirm this point, the proposed paper identifies the major contributors to academic journals regarding the relationships between wine polyphenols and health. The endpoints of the proposed study are to provide a comprehensive overview and analysis of the literature regarding the relationships between wine polyphenol and health based on a bibliometric analysis. Bibliometric data were extracted from the Scopus online database using the search string TITLE-ABS-KEY (wine AND polyphenol* AND health OR ("french paradox" OR "cardiovascular disease*" OR atherosclerosis OR microbiota) and analyzed using the VOSviewer bibliometric software to generate bubble maps and to visualize the obtained results. This perspective paper analyzes: (i) the research themes addressing the relationships between wine polyphenols and health; (ii) the major contributors' origin, e.g., country and/or regions; (iii) the institutions where the research is based; (iv) the authors; and (v) the type of paper. These results represent a useful tool to identify emerging research directions, collaboration networks, and suggestions for more in-depth literature searches. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the antimicrobial activity as natural disinfect of traditional wine with total aerobic plate count method. Samples were collected from poultry and pig farms. The swab samples were analyzed for amount of microbial contamination. The results showed that there is a significant difference in the amount of microbial contamination. The amount of microbial contamination was lower after the application of natural traditional drinks, namely Sopi and Moke, in poultry and pig farms as compared to commercial disinfectants. The results indicate that Sopi and Moke can be used as a natural disinfectant as alternate to chemical disinfectants. [ABSTRACT FROM AUTHOR]

Global warming is causing serious problems, especially, in warm regions, where musts with excess sugars and high pH produce wines with decreased freshness and unstable evolution. This study aimed to determine biocompatibility between yeast species, the capacity for microbiological acidification, and the aromatic profile produced in ternary fermentations in which Lachancea thermotolerans has been co-inoculated with Hanseniaspora vineae , Torulaspora delbrueckii , or Metschnikowia pulcherrima , and the fermentation process is subsequently completed with sequential inoculation of Saccharomyces cerevisiae. For this purpose, different cell culture media and instruments were used such as infrared spectroscopy, enzymatic autoanalyzer, chromatograph coupled with a flame ionization detector, spectrophotometric analysis, among others. The behavior of these yeasts was evaluated alone and in co-inoculation, always finishing the fermentation with sequential inoculation of S. cerevisiae , at a stable temperature of 16°C and with a low level of sulfites (25 mg/L) in white must. Significant results were obtained in terms of biocompatibility using population counts (CFU/ml) in differential plating media that permitted monitoring. Quantification of the five species was studied. Concerning acidification by L. thermotolerans in co-inoculations, we showed some metabolic interactions, such as the inhibition of acidification when H. vineae / L. thermotolerans were used, generating just over 0.13 g/L of lactic acid and, conversely, a synergistic effect when M. pulcherrima / L. thermotolerans were used, achieving 3.2 g/L of lactic acid and a reduction in pH of up to 0.33. A diminution in alcohol content higher than 0.6% v/v was observed in co-inoculation with the L. thermotolerans / M. pulcherrima yeasts, with total sugar consumption and very slow completion of fermentation in the inoculations with H. vineae and T. delbrueckii. The aromatic composition of the wines obtained was analyzed and a sensory evaluation conducted, and it was found that both L. thermotolerans and co-inoculations retained more aromatic esters over time and had a lower evolution toward the yellow tones typical of oxidation and that the best sensory evaluation was that of the Lt + Mp co-inoculation. Lachancea thermotolerans and co-inoculations produced wines with low levels of volatile acidity (<0.4 g/L). This work shows that good consortia strategies with binary and ternary fermentations of yeast strains can be a powerful bio-tool for producing more complex wines. [ABSTRACT FROM AUTHOR]

The production of wines with peculiar analytical and sensorial profiles, together with the microbiological control of the winemaking process, has always been one of the main objectives of the wine industry. In this perspective, the use of oenological starters containing non-Saccharomyces yeasts can represent a valid tool for achieving these objectives. Here we present the results of seven pilot scale fermentations, each of which was inoculated with a different non-Saccharomyces yeast strain and after three days with a commercial Saccharomyces cerevisiae starter. The fermentations were carried out in double on 70 L of Sangiovese grape must, the most widely planted red grape variety in Italy and particularly in Tuscany, where it is utilized for the production of more than 80% of red wines. Fermentations were monitored by assessing both the development of the microbial population and the consumption of sugars at the different sampling times. The impact of the different starters was assessed after stabilization through the evaluation of the standard analytical composition of the resulting wines, also taking into account polysaccharides and volatile compounds. Moreover, quantitative descriptive sensory analyses were carried out. Compared to the control wines obtained by inoculating the S. cerevisiae starter strain, those inoculated with non-Saccharomyces/Saccharomyces mixed starters presented a significant differentiation in the chemical-analytical composition. Moreover, sensory analysis revealed differences among wines mainly for intensity of color, astringency, and dryness mouthfeel perception. [ABSTRACT FROM AUTHOR]

Malolactic fermentation (MLF) in wine is an important step in the vinification of most red and some white wines, as stands for the biological conversion of l-malic acid into l-lactic acid and carbon dioxide, resulting in a decrease in wine acidity. MLF not only results in a biological deacidification, it can exert a significant impact on the organoleptic qualities of wine. This paper reviews the biodiversity of lactic acid bacteria (LAB) in wine, their origin, and the limiting conditions encountered in wine, which allow only the most adapted species and strains to survive and induce malolactic fermentation. Of all the species of wine LAB, Oenococcus oeni is probably the best adapted to overcome the harsh environmental wine conditions and therefore represents the majority of commercial MLF starter cultures. Wine pH is most challenging, but, as a result of global warming, Lactobacillus sp. is more often reported to predominate and be responsible for spontaneous malolactic fermentation. Some Lactobacillus plantarum strains can tolerate the high alcohol and SO2 levels normally encountered in wine. This paper shows the potential within this species for the application as a starter culture for induction of MLF in juice or wine. Due to its complex metabolism, a range of compositional changes can be induced, which may positively affect the quality of the final product. An example of a recent isolate has shown most interesting results, not only for its capacity to induce MLF after direct inoculation, but also for its positive contribution to the wine quality. Degrading hexose sugars by the homo-fermentative pathway, which poses no risk of acetic acid production from the sugars, is an interesting alternative to control MLF in high pH wines. Within this species, we can expect more strains with interesting enological properties. [ABSTRACT FROM AUTHOR]

Fresh "Xuxiang" kiwifruit juice with or without pomace was used for fermentation with different levels of glutathione‐enriched inactive dry yeast (g‐IDY). After alcohol fermentation, the glutathione (GSH) content, color parameters, phenolic composition, and antioxidant activities of kiwi wine were determined. The results suggested that the addition of g‐IDY to kiwi juice increased GSH, glutathione disulfide, total GSH concentrations, and the total phenolic content of kiwi wine. No obvious effect on individual phenolic content was found in wine with g‐IDY. The color parameters of wines fermented with pomace were remarkably improved with addition of 100 mg/L and 300 mg/L g‐IDY. The supply of g‐IDY improved the antioxidant activities of kiwi wine fermented with pomace. Principal component analysis suggested that with the same supplies of g‐IDY, wine fermented with pomace was better than wine fermented through pure juice in all measurements. Practical applications: The improvements in color and antioxidant capacity of kiwi wine have always been the focus of kiwi wine brewing. Constant improvement in methods which contribute to high quality of kiwi wine provides crucial support for wine industry and even agriculture development. The aim of this study is to investigate the impacts of glutathione‐enriched inactive dry yeast (g‐IDY) on quality of kiwi wine. These results could provide feasible advices about g‐IDY application to kiwi wine for improving the sensory and nutritional properties. [ABSTRACT FROM AUTHOR]

The content of ascorbic acid and phenolic substances has been investigated in natural juices and unfortified wine materials obtained from garden strawberries of the varieties Polka and Pegasus. The juices considered contained 271–417 mg/dm3 of ascorbic acid, and 1280–1500 mg/dm3 of phenolic substances. The content of these ingredients depends on the varietal characteristics. To prepare unfortified wine materials for dessert wines, 230 g of white sugar was added to one dm3 of strawberry juice. The must was pasteurised at 85°C for 5 minutes, cooled, and fermented with active dry yeast. The yeast was of the races EC 1118 (France), ENSIS LE-C1, ENSIS LE-1, ENSIS LE-5, ENSIS LE-6 (Spain), which were used in accordance with the manufacturers’ recommendations. It has been found that the content of ascorbic acid and phenolic substances decreases while musts are being prepared and fermented. The average loss of ascorbic acid during must preparation is 17.4%, and that of phenolic substances is 1.1–4.9%. A decrease in these components due to dilution with sugar in the course of must preparation is 14–15%. Fermentation of strawberry musts, with the initial concentration of invert sugars 274 g/dm3, lasts 70–77 days. The yield of cleared wine material after fermentation depends on the varietal characteristics and the yeast race used, and ranges 86.9 to 92.7%. The loss of ascorbic acid during must fermentation averages 49.3%, and that of phenolic substances 21.6%. Strawberry-based unfortified wine materials have been found to contain 86–158 mg/dm3 of ascorbic acid and 720–1080 mg/dm3 of phenolic substances. In particular, according to the average data of two years’ research, the content of phenolic substances in wine materials from strawberries of the Polka variety was by 197 mg/dm3 higher than their content in wine materials from the Pegasus variety. The wine materials retain 25.4–41.3% (33.6% on average) of ascorbic acid contained in juices (and in fresh berries, too), and 56.2–72.0% of phenolic substances (62.6% on average). The yeast race ENSISLE-C1 (Spain) should be used for better preservation of ascorbic acid, and EC-1118 (France) should be used to preserve phenolic substances. The research results confirm that unfortified dessert wines from strawberries can be regarded as products with preventive capacities. [ABSTRACT FROM AUTHOR]

Vitis vinifera cv. Narince is a Turkish native white grape variety. In this study, volatile and sensory properties of Narince wines that are produced with autochthonous Saccharomyces cerevisiae (S. cerevisiae) strains and commercial strain were compared. Autochthonous yeast strains 1044 (MG017575), 1088 (MG017577), and 1281 (MG017581) were previously isolated from spontaneous fermentations of Narince grapes. Volatile compounds formed in wines were extracted using a liquid-liquid extraction method and determined by GC-MS-FID. All yeast strains fermented Narince grape juice to dryness. The differences between the volatile profiles of the yeast strains were determined. Wines fermented with autochthonous strains 1281 and 1044 produced a higher amount of acetates and ethyl esters. While the highest concentrations of ethyl hexanoate and hexyl acetate were found in wine fermented with 1044, the highest concentrations of ethyl octanoate, ethyl decanoate, isoamyl acetate, and 2-phenylethyl acetate were found in wine fermented with strain 1281. Also, the highest contents of 2-phenyl ethanol and linalool were found in wine fermented with strain 1281. According to sensory analysis, the wine fermented with 1281 achieved the best scores in floral and fruity attributes, as well as balance and global impression. The data obtained in the present study showed that autochthonous yeast strains affect the final physicochemical composition and sensory profile of Narince wines. [ABSTRACT FROM AUTHOR]

Traditional sparkling wines are produced by the refermentation of a base wine with yeast in the bottle followed by a critical period of aging. During the often lengthy aging process, yeast undergoes cell death and autolysis to release cellular compounds that over time ultimately contribute to the flavor and appearance of the product. While accelerating yeast autolysis for sparkling wine production has been the focus of several studies, employing overexpressed native yeast alleles for this purpose remains poorly explored. Here, we show that the overexpression of native yeast genes, specifically selected autophagic genes, results in accelerated cell death in nitrogen starvation and base wine refermentation. We show ATG3 or ATG4 overexpression has pleiotropic intracellular ramifications including reduced turnover of autophagic cargo, vacuolar fragmentation, abnormal accumulation of lipids, and accelerated accumulation of reactive oxygen species (ROS), all of which precede accelerated cell death. Our findings suggest that the increased expression of autophagy-related genes, such as ATG3 and ATG4, in industrial wine yeast can serve as a suitable marker or breeding strategy to accelerate the cell death and autolysis of wine yeast during sparkling wine production. [ABSTRACT FROM AUTHOR]

Apiculate yeasts of the genus Hanseniaspora/Kloeckera are the main species present on mature grapes and play a significant role at the beginning of fermentation, producing enzymes and aroma compounds that expand the diversity of wine color and flavor. Ten species of the genus Hanseniaspora have been recovered from grapes and are associated in two groups: H. valbyensis, H. guilliermondii, H. uvarum, H. opuntiae, H. thailandica, H. meyeri, and H. clermontiae; and H. vineae, H. osmophila, and H. occidentalis. This review focuses on the application of some strains belonging to this genus in co-fermentation with Saccharomyces cerevisiae that demonstrates their positive contribution to winemaking. Some consistent results have shown more intense flavors and complex, full-bodied wines, compared with wines produced by the use of S. cerevisiae alone. Recent genetic and physiologic studies have improved the knowledge of the Hanseniaspora/Kloeckera species. Significant increases in acetyl esters, benzenoids, and sesquiterpene flavor compounds, and relative decreases in alcohols and acids have been reported, due to different fermentation pathways compared to conventional wine yeasts. [ABSTRACT FROM AUTHOR]

The interest in non-Saccharomyces yeast for use in sparkling wine production has increased in recent years. Studies have reported differences in amino acids and ammonia, volatile aroma compounds (VOCs), glycerol, organic acids, proteins and polysaccharides. The aim of this review is to report on our current knowledge concerning the influence of non-Saccharomyces yeast on sparkling wine chemical composition and sensory profiles. Further information regarding the nutritional requirements of each of these yeasts and nutrient supplementation products specifically for non-Saccharomyces yeasts are likely to be produced in the future. Further studies that focus on the long-term aging ability of sparkling wines made from non-Saccharomyces yeast and mixed inoculations including their foam ability and persistence, organic acid levels and mouthfeel properties are recommended as future research topics. [ABSTRACT FROM AUTHOR]

The potential of ultra-fast gas chromatography (GC) combined with chemometric analysis for classification of wine originating from Poland according to the variety of grape used for production was investigated. A total of 44 Polish wine samples differing in the type of grape (and grape growth region) used for the production as well as parameters of the fermentation process, alcohol content, sweetness, and others which characterize wine samples were analysed. The selected features coming from ultra-fast GC analysis were subsequently used as inputs for both principal component analysis (PCA) and supervised machine learning. Using the proposed classification algorithm, it was possible to classify white and red wines according to the variety of grape used for production with a 98.7 and 98.2% accuracy, respectively. The model was characterized by good recall and area under receiver operating characteristic which was 1.000 for white wines and 0.992 for red wines. Cuveé wines (made from various types of grapes) were also successfully classified which leads to the conclusion that the proposed classification method can be used not only to differentiate between wines made from different grapes but also to detect possible adulterations, provided known; non-adulterated samples are available as a reference. The model was also used to classify wine samples based on other features, such as the geographic region in which the vineyard is situated, type of yeast used, the temperature of fermentation, sweetness, etc. In all cases, a high classification accuracy (in most cases > 90%) was achieved. The obtained results could be applied in the wine industry. [ABSTRACT FROM AUTHOR]

The most common way to produce red wine is through the use of Saccharomyces cerevisiae strains for alcoholic fermentation and lactic acid bacteria for malolactic fermentation. This traditional winemaking methodology produces microbiologically stable red wines. However, under specific conditions off-flavours can occur, wine quality can suffer and human health problems are possible, especially after the second fermentation by the lactic acid bacteria. In warm countries, problems during the malolactic fermentation arise because of the high pH of the must, which makes it very difficult to properly control the process. Under such conditions, wines with high acetic acid and histamine concentrations are commonly produced. This study investigates a recent red wine-making technology that uses a combination of Lachancea thermotolerans and Schizosaccharomyces pombe as an alternative to the conventional malolactic fermentation. This work studies new parameters such as aroma compounds, amino acids, ethanol index and sensory evaluation. Schizosaccharomyces pombe totally consumes malic acid while Lachancea thermotolerans produces lactic acid, avoiding excessive deacidification of musts with low acidity in warm viticulture areas. This methodology also reduces the malolactic fermentation hazards in wines with low acidity. The main products are wines that contain less acetic acid, less biogenic amines and precursors and less ethyl carbamate precursors than the traditional wines produced via conventional fermentation techniques. [ABSTRACT FROM AUTHOR]

This work represents the first study on the biotransformation of chemical constituents of durian wine via simultaneous alcoholic fermentation (AF) and malolactic fermentation (MLF) with non- Saccharomyces yeast and lactic acid bacteria (LAB), namely, Torulaspora delbrueckii Biodiva and Oenococcus oeni PN4. The presence of PN4 improved the utilization of sugars but did not affect ethanol production. MLF resulted in the significant degradation of malic acid with corresponding increases in pH and lactic acid. The final concentrations of acetic acid (1.29 g/L) and succinic acid (3.70 g/L) in simultaneous AF and MLF were significantly higher than that in AF (1.05 and 1.31 g/L) only. Compared with AF, simultaneous AF and MLF significantly elevated the levels of aroma compounds with higher levels of higher alcohols (isoamyl alcohol, active amyl alcohol, isobutyl alcohol, and 2-phenylethyl alcohol), acetate esters (ethyl acetate, isoamyl acetate), and ethyl esters (ethyl octanoate, ethyl dodecanoate). All the endogenous volatile sulfur compounds decreased to trace or undetectable levels at the end of fermentation. MLF accentuated the reduction of acetaldehyde and sulfides. The initially absent dipropyl disulfide was formed, then catabolized, especially in simultaneous AF and MLF. This study suggested that the simultaneous AF and MLF of non- Saccharomyces and LAB could modify the volatile compositions and potentially modulate the organoleptic properties of durian wine. [ABSTRACT FROM AUTHOR]

This mini-review synthesises the present knowledge of microbial quorum-sensing, with a specific focus on quorum-sensing in yeast, and especially in wine yeast. In vine and wine ecosystems, yeast co-interact with a large variety of microorganisms, thereby affecting the fermentation process and, consequently, the flavour of the wine. The precise connections between microbial interactions and quorum-sensing remain unclear, but we describe here how and when some species start to produce quorum-sensing molecules to synchronously adapt their collective behaviour to new conditions. In Saccharomyces cerevisiae, the quorum-sensing molecules were identified as 2-phenylethanol and tryptophol. However, it was recently shown that also a quorum-sensing molecule formerly identified only in Candida albicans, tyrosol, appears to be regulated in S. cerevisiae according to cell density. This review describes the methods for detection and quantification of those quorum-sensing molecules, their underlying mechanisms of action, and their genetic background. It also examines the external stimuli that evoke the quorum-sensing mechanism in the wine-processing environment. The review closes with insight into the biotechnological applications that are already making use of the advantages of quorum-sensing systems and indicates the important questions that still need to be addressed in future research into quorum-sensing. [ABSTRACT FROM AUTHOR]

This study evaluates the influence of Lachancea thermotolerans on low-acidity Airén grape must from the south of Spain. For this purpose, combined fermentations with Lachancea thermotolerans and Saccharomyces cerevisiae were compared to a single fermentation by S. cerevisiae. Results of all developed analyses showed significant diff erences in several parameters including acidity, population growth kinetics, concentration of amino acids, volatile and non-volatile compounds, and sensorial parameters. The Airén wine quality increased mainly due to the acidifi cation by L. thermotolerans. The acidifi cation process caused a lactic acid increment of 3.18 g/L and a reduction of 0.22 in pH compared to the control fermentation, performed by S.cerevisiae. [ABSTRACT FROM AUTHOR]

Yeast starter cultures for winemaking have traditionally been developed from successful fermentation isolates. Over the past 10-20 years there has been a move to harness genetic techniques to improve production strains. The approaches to achieve this have been similar to those applied in the agricultural sector for crop and livestock development. Thus, domestication of wine yeasts now involves hybridisation, mutagenesis, selection and screening. There is also a growing interest in tapping into isolates of non-Saccharomyces yeasts to develop novel starter cultures that bring complexity and potentially enhance regionality of wines. This review will cover these developments and will look to the future opportunities arising from the application of genetic engineering and synthetic biology approaches for the introduction of novel phenotypes that are outside of the reach of traditional methods. [ABSTRACT FROM AUTHOR]

Wine yeast, from production to application, traverse an incredible range of environments. Central to their ability to not only survive but to thrive throughout this journey is their capacity to transform themselves in response to the varied conditions encountered. Wine yeast resilience alone, however, is insufficient. Producers and winemakers must be assiduous in their use of wine yeast with an understanding of yeast requirements throughout the process to achieve optimal results. Active dried yeast (ADY) starter cultures for initiating grape must fermentations are convenient, reliable and available for a wide range of strains suited to different wine types. These benefits cannot be fully realised without optimisation of: their production; reactivation of the dried product prior to inoculation; and appropriate nutrient management during fermentation. This review discusses current knowledge on production of Saccharomyces ADY for greatest biological stability and activity, and factors that affect their activity following rehydration and inoculation into grape must. The efficacy of various types of commercial additives used in reactivation of ADY and, winemaking interventions and nutrients that are used to optimise fermentation are also discussed. [ABSTRACT FROM AUTHOR]

BACKGROUND The aim of this paper is to determine the main factors that influence the foaming properties of base wines and sparkling wines and, in particular, the role played by the maturity of the grapes in the controlled designation of origin ( CDO) Cava. Macabeo, Xarel.lo, Parellada and Chardonnay grapes were harvested at two different maturity levels in two vintages. The first harvest was selected because of its desirable titratable acidity and the second because of its optimal sugar concentration. The mono-varietal base wines and standard blends were transformed into sparkling wines and aged for 14 months. RESULTS The results indicate that the main factors affecting foam properties are ethanol content, high molecular weight polysaccharides and gluconic acid (which have a negative effect), and proteins (which have a positive effect). CONCLUSION The main conclusion of this study is that the foaming properties of wines can be improved if harvest dates are advanced. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

One of the issues that most concerns to both winemakers and producers of active dry yeasts is the stuck and sluggish fermentations of grape musts with high levels of sugar, reflecting the inability of inoculated yeast strain to complete the fermentation process. It is difficult to obtain a wine strain that possesses both adequate oenological and technological properties; thus, the correct approach to solving these problems is the application of breeding programs primarily focused on both properties. The first step toward this process is to characterize the phenotypic diversity between potential parental strains. In the present study, we have analyzed the fermentative behavior of 26 Saccharomyces cerevisiae wine strains in high-sugar conditions at 20 °C, using a range of tests, such as sporulation ability, spore viability, and tetrad analysis to determine the tolerance of these yeasts to several stress conditions. Most tested strains were homothallic and heterozygous for more than one character. Two auxotrophic derivatives with defects in amino acid or nucleic acid metabolism were obtained, and these strains could potentially be used for the development of hybridization techniques without using laboratory strains. [ABSTRACT FROM AUTHOR]

The wine sector is actively seeking strategies and technologies that facilitate the production of wines with lower alcohol content. One of the simplest approaches to achieve this aim would be the use of wine yeast strains which are less efficient at transforming grape sugars into ethanol; however, commercial wine yeasts have very similar ethanol yields. We recently demonstrated that Metschnikowia pulcherrima AWRI1149 was able to produce wine with reduced alcohol concentration when used in sequential inoculation with a wine strain of Saccharomyces cerevisiae. Here, different inoculation regimes were explored to study the effect of yeast population dynamics and potential yeast interactions on the metabolism of M. pulcherrima AWRI1149 during fermentation of non-sterile Shiraz must. Of all inoculation regimes tested, only ferments inoculated with M. pulcherrima AWRI1149 showed reduced ethanol concentration. Population dynamics revealed the presence of several indigenous yeast species and one of these, Saccharomyces uvarum (AWRI 2846), was able to produce wine with reduced ethanol concentration in sterile conditions. Both strains however, were inhibited when a combination of three non- Saccharomyces strains, Hanseniaspora uvarum AWRI863, Pichia kluyveri AWRI1896 and Torulaspora delbrueckii AWRI2845 were inoculated into must, indicating that the microbial community composition might impact on the growth of M. pulcherrima AWRI1149 and S. uvarum AWRI 2846. Our results indicate that mixed cultures of M. pulcherrima AWRI1149 and S. uvarum AWRI2846 enable an additional reduction of wine ethanol concentration compared to the same must fermented with either strain alone. This work thus provides a foundation to develop inoculation regimes for the successful application of non- cerevisiae yeast to the production of wines with reduced alcohol. [ABSTRACT FROM AUTHOR]

ABSTRACT The evolution of sensory characters of white wine cellared under ideal conditions has not previously been studied extensively. The effect of 3 years of bottle ageing of 16 commercial Hunter Valley Semillon (HVS) has been investigated by sensory descriptive analysis. Overall, although primary fruit characters (lemon/lime, grassy, floral, grapefruit and pineapple) generally decreased, some attributes, particularly lemon/lime, remained important features of the wine after the ageing period. Although the grapefruit aroma decreased in all but one wine, none of the decreases were found to have been significant ( p < 0.05). Developed characters such as honey, toast and orange marmalade also became more prominent. This study also provides an illustration of the sensory changes in bottled HVS with regard to previously identified HVS styles, with the most noticeable changes occurring in styles categorized by primary fruit characters. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Alcoholic fermentation by an oenological strain of Torulaspora delbrueckii in association with an oenological strain of Saccharomyces cerevisiae was studied in mixed and sequential cultures. Experiments were performed in a synthetic grape must medium in a membrane bioreactor, a special tool designed to study indirect interactions between microorganisms. Results showed that the S. cerevisiae strain had a negative impact on the T. delbrueckii strain, leading to a viability decrease as soon as S. cerevisiae was inoculated. Even for high inoculation of T. delbrueckii (more than 20× S. cerevisiae) in mixed cultures, T. delbrueckii growth was inhibited. Substrate competition and cell-to-cell contact mechanism could be eliminated as explanations of the observed interaction, which was probably an inhibition by a metabolite produced by S. cerevisiae. S. cerevisiae should be inoculated 48 h after T. delbrueckii in order to ensure the growth of T. delbrueckii and consequently a decrease of volatile acidity and a higher isoamyl acetate production. In this case, in a medium with a high concentration of assimilable nitrogen (324 mg L), S. cerevisiae growth was not affected by T. delbrueckii. But in a sequential fermentation in a medium containing 176 mg L initial assimilable nitrogen, S. cerevisiae was not able to develop because of nitrogen exhaustion by T. delbrueckii growth during the first 48 h, leading to sluggish fermentation. [ABSTRACT FROM AUTHOR]

Background and Aims Interactions between different yeast species used as starters may lead to inconsistent results in mixed fermentations. The aim of this study was to assess the influence of different nutrients on the association between a wine strain of C andida zemplinina ( CDZ1) and a commercial wine strain of S accharomyces cerevisiae ( EC1118) in mixed culture fermentations. Methods and Results Laboratory-scale fermentations were carried out by inoculating CDZ1 and, after 3 days, EC1118 with the simultaneous addition of diammonium phosphate, yeast hulls, ergosterol and oleic acid, each provided separately. The addition of yeast hulls resulted in a higher cell population of CDZ1 and in a higher glycerol concentration of wine as compared with that of the other fermentations. Pilot-scale fermentations, carried out in a commercial winery, confirmed that the winemaking protocol based on the use of the mixed starters CDZ1/ EC1118 with added yeast hulls results in wine with a higher glycerol content, more structured and persistent. Conclusions Addition of yeast hulls improved the fermentative performance of the mixed starters CDZ1/ EC1118. Significance of the Study The high glycerol content of wines made with the combined use of yeast hulls and CDZ1/ EC1118 mixed starters increases wine softness and body. [ABSTRACT FROM AUTHOR]

Oenococcus oeni is a multiple physical stress-tolerant lactic acid bacterium that plays an important role in wine making. It is often added as a starter culture to carry out malolactic fermentation (MLF). In this study, a total of 22 out of 127 lactic acid bacteria, isolated from Chinese wines undergoing MLF, were identified as O. oeni by species-specific PCR and 16S rRNA sequencing. Single-enzyme amplified fragment length polymorphism (SE-AFLP) analysis showed that all strains could be typed under these conditions, and three main groups were determined by cluster analysis, which showed intraspecific homology higher than 69 %. Eight strains, representative of SE-AFLP clusters, were tested for malolactic activity. Significant differences were observed among strains with regard to the amount of malic acid consumed. Seventeen amino acids in different wines that were inoculated by 4 O. oeni strains, respectively, were analyzed before and after MLF. The results indicated that the amino acid metabolism of the 4 strains was significantly different between each strain. [ABSTRACT FROM AUTHOR]

The yeast Torulaspora delbrueckii is associated with several human activities including oenology, bakery, distillery, dairy industry, etc. In addition to its biotechnological applications, T. delbrueckii is frequently isolated in natural environments (plant, soil, insect). T. delbrueckii is thus a remarkable ubiquitous yeast species with both wild and anthropic habitats, and appears to be a perfect yeast model to search for evidence of human domestication. For that purpose, we developed eight microsatellite markers that were used for the genotyping of 110 strains from various substrates and geographical origins. Microsatellite analysis showed four genetic clusters: two groups contained most nature strains from Old World and Americas respectively, and two clusters were associated with winemaking and other bioprocesses. Analysis of molecular variance (AMOVA) confirmed that human activities significantly shaped the genetic variability of T. delbrueckii species. Natural isolates are differentiated on the basis of geographical localisation, as expected for wild population. The domestication of T. delbrueckii probably dates back to the Roman Empire for winemaking (∼1900 years ago), and to the Neolithic era for bioprocesses (∼4000 years ago). Microsatellite analysis also provided valuable data regarding the life-cycle of the species, suggesting a mostly diploid homothallic life. In addition to population genetics and ecological studies, the microsatellite tool will be particularly useful for further biotechnological development of T. delbrueckii strains for winemaking and other bioprocesses. [ABSTRACT FROM AUTHOR]

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The work presents the essence of the secondary fermentation occurring in the course of grape wines production—malolactic fermentation (MLF). The selection of wine yeast and bacteria preparations, scenario of malolactic bacteria inoculation as well as control system of the process conditions are proposed to create the specific character and style of grape wines produced in cool-climate countries, in which the acidity of grape must is often significantly enhanced and the concentration of aroma compounds is considerably low. The role played by appropriately run MLF is presented, along with the advantages and disadvantages of the process, benefits, and technological drawbacks resulting from the introduction of this procedure to the vinification process. Moreover, methods to initiate and run MLF as well as interactions occurring between microorganisms used in wine production, i.e., wine yeasts from the genus Saccharomyces and wine bacteria from the genus Oenococcus, are also presented and discussed. [ABSTRACT FROM AUTHOR]

The present study sought to optimize fresh wine yeast biomass production in an aerated fermenter fed with different volumes of concentrated grape must. Variables most likely to influence the process were tested at high and low levels, in a total of 13 fermentation runs. The production process was scaled up to pilot plant level, and the yeasts thus obtained were inoculated into wine fermentation tanks in a winery to evaluate their implantation during alcoholic fermentation. The best fermentation conditions were those used for batches carried out at 34C, 15° Brix and initial inoculum of 5.0 × 107 cells/ mL; in these cases, cells displayed high protein and phosphorus content, a good P2O5/ N ratio and appreciable accumulation of intracellular trehalose, indicating that the process was not too much stressful. Generally, biomass exhibited adequate vitality throughout storage (80%). The yeast produced retained a high degree of vitality and viability after 2 weeks of refrigeration; for this, seasonal production could, to some extent, be matched to the needs of the winery. Small-scale laboratory production of fresh yeast biomass could help small wineries enhance the concept of terroir. This study confirmed that small amounts of fresh biomass can be sufficient as inoculum in winemaking. Practical Applications This research is related to small-scale production of grade yeast using concentrated grape must. It has important practical applications, useful in small wine cellars. At the beginning of the vintage, the oenologist could produce their own selected yeasts and used them in wine-making process, as biomass showed a high vitality/viability degree after 2 weeks of storage at 4C. Moreover, biomass is easier to use in small wineries, so it ensures uniform dispersal, and in the conditions studied, the biomass obtained is sufficient to inoculate tanks with an inoculum of 106 cells/ mL. [ABSTRACT FROM AUTHOR]

In this work we have critically revised and updated the literature dealing with wine quality control based on protein or peptide mass spectrometry-based fingerprinting. A number of pitfalls in the experimental design of most work dealing with this subject are highlighted along with recommendations on how to circumvent them. As a general trend, the conclusions reported to date in the literature of the topic are inconclusive mainly due to the (i) low number of representative samples, (ii) lack of basic analytical concepts, and (iii) lack of adequate statistical and software tools. In addition, we have critically revised the sample treatments commonly used to separate proteins from wines, emphasizing that the majority of literature is devoted to white wines, probably because of difficulties in isolating the protein content in red wines. [ABSTRACT FROM AUTHOR]

Alcoholic fermentation of grape must is a complex process, involving several yeast genera and species. The early stages in fermentation are dominated by non- Saccharomyces yeasts that are gradually replaced by the Saccharomyces cerevisiae species, which takes over the fermentation. Quantitative studies have reported the influence of non- Saccharomyces yeast species on wine quality and evaluated their biotechnological interest. The industrial yeast market, which, until recently, exclusively focused on S. cerevisiae, now offers S. cerevisiae/non- Saccharomyces (including Torulaspora delbrueckii) multi-starters. The development of these new mixed industrial starters requires a better understanding of the interaction mechanisms between yeast populations in order to optimize the aromatic impact of the non- Saccharomyces yeast while ensuring complete alcoholic fermentation thanks to S. cerevisiae. For this purpose, a new double-compartment fermentor was designed with the following characteristics: (1) physical separation of two yeast populations, (2) homogeneity of the culture medium in both compartments, (3) fermentation kinetics monitored by weight loss due to CO release, and (4) independent monitoring of growth kinetics in the two compartments. This tool was used to compare mixed inoculations of S. cerevisiae/ T. delbrueckii with and without physical separation. Our results revealed that physical contact/proximity between S. cerevisiae and T. delbrueckii induced rapid death of T. delbrueckii, a phenomenon previously described and attributed to a cell-cell contact mechanism. In contrast, when physically separated from S. cerevisiae, T. delbrueckii maintained its viability and its metabolic activity had a marked impact on S. cerevisiae growth and viability. The double fermentor is thus a powerful tool for studying yeast interactions. Our findings shed new light on interaction mechanisms described in microorganism populations. [ABSTRACT FROM AUTHOR]

A novel, robust and fast ultra-high performance liquid chromatography-MS method has been developed for the simultaneous quantification of reduced glutathione (GSH) and oxidised glutathione (GSSG) in grape juice, wine and model wine solution. Sample preparation is minimal and does not require derivatisation. The method has very good performance in terms of sensitivity and selectivity. The limit of detection was 0.002 and 0.001 mg L−1 for GSH and GSSG, respectively. The amount of GSH and GSSG released by commercial glutathione-enriched inactivated dry yeast preparations (GSH-IDYs) into a model solution was assessed. Significant differences in the amount of GSH and/or GSSG released into a model wine by different GSH-IDYs were observed, with ethanol influencing this release under certain conditions. The GSH and GSSG levels in grape juice fermentations supplemented with GSH-IDY were also assessed in relation to different addition times during fermentation. GSH-IDY addition can lead to elevated wine GSH levels, provided the supplementation is done early during alcoholic fermentation. [ABSTRACT FROM AUTHOR]

The impact of the addition of fusel oil or amino acids on the volatile compounds in papaya wine fermented with a mixed culture of Saccharomyces cerevisiae var. bayanus R2 and Williopsis saturnus var. mrakii NCYC 2251 at a ratio of 1:1000 was studied. Fusel oil addition increased the fraction of alcohols and promoted the production of isoamyl octanoate, isoamyl decanoate and isobutyl decanoate, while decreased the fraction of ethyl acetate and 2-phenylethyl acetate. The addition of amino acids enhanced the formation of total volatile fatty acids, 2-phenylethanol and some ethyl esters. The papaya wine with added amino acids possessed more acidic and buttery notes than the control, while that with added fusel oil had an overall aroma profile comparable to that of the control. This study suggests that papaya juice fermentation with mixed yeasts in conjunction with the added fusel oil or selected amino acids may be another method of modulating the flavour of papaya wine. [ABSTRACT FROM AUTHOR]

Oxygen has a fundamental role in the vinification process and occurs in the various stages, particularly during the fermentation and aging of wines. Phenolic compounds, such as oxygen, are relatively important in wine quality. Among polyphenols, anthocyanins and tannins are the most important compounds since they contribute to the organoleptic characteristics of wines, particularly colour and astringency. During wine-making and aging, phenolics extracted from grapes gradually change owing to biochemical reactions, which result in a decrease in astringency as well as colour stabilization. Therefore, addition of a measured amount of oxygen, referred to as a microoxygenation process, was proposed to improve wine quality by accelerating these transformations of phenols. In a microoxygenation process, it is assumed that modification of phenolic compound reactions by oxidation should result in more coloured and less astringent products. In this article, the role of oxygen, phenolics and microoxygenation application in wine technology has been reviewed. Copyright © 2013 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Headspace solid-phase dynamic extraction (HS-SPDE) was investigated for its applicability in quality control analysis of wine volatiles using gas chromatography-mass spectrometry. In total, 196 German red wines were analysed and 22 flavour-relevant alcohols and esters were quantified. The method detection limits were between 0.1 and 9.3 μg L, allowing the dilution of the samples to decrease matrix and competition effects. Quantification resulted in a concentration range from about 1 μg L linalool up to 380 mg L 2-methyl-1-propanol. The measurement uncertainty budget was determined for all compounds in a 'top-down' approach and was between 2.5 and 7.9 %, with an average of 5.5 %. A surveillance of the extraction performance of the HS-SPDE devices showed constant results for up to 400 extractions using one extraction needle tip. A chromatogram library for quality and authenticity control of wine samples was created using commercially available chromatogram comparison software. [ABSTRACT FROM AUTHOR]

The impact of Torulaspora delbrueckii has been investigated for the first time in the production of Amarone wine, a high-alcohol dry red wine obtained from withered grapes. In two different vinifications, winery trials were inoculated by a selected strain of T. delbrueckii simultaneously and/or sequentially to Saccharomyces cerevisiae. Implantation analysis demonstrated T. delbrueckii was able to rapidly colonise the must remaining in wine up to 16.5 % v v of ethanol. The effects of T. delbrueckii on the aroma of Amarone wine were linked to its persistence during the fermentation and a great number of compounds varied in wine obtained with mixed cultures. The most significant changes were observed among alcohols, fermentative esters, fatty acids and lactones, which are important in the Amarone wine flavour. This study confirms the role of T. delbrueckii on wine aroma and the potential of non- Saccharomyces use in winemaking. [ABSTRACT FROM AUTHOR]

During malolactic fermentation (MLF), lactic acid bacteria influence wine aroma and flavour by the production of volatile metabolites and the modification of aroma compounds derived from grapes and yeasts. The present study investigated the impact of different MLF inoculation strategies with two different Oenococcus oeni strains on cool climate Riesling wines and the volatile wine aroma profile. Four different timings were chosen for inoculation with bacteria to conduct MLF in a Riesling must/wine with a high acidity (pH 2.9-3.1). Treatments with simultaneous inoculation showed a reduced total fermentation time (alcoholic and malolactic) compared to the sequential inoculations. No negative impact of simultaneous alcoholic and malolactic fermentation on fermentation success and on the final wine volatile aroma composition was observed. Compared to sequential inoculation, wines with co-inoculation tended to have higher concentrations of ethyl and acetate esters, including acetic acid phenylethylester, acetic acid 3-methylbutylester, butyric acid ethylester, lactic acid ethylester and succinic acid diethylester. Results of this study provide some alternatives to diversify the number of wine styles by safely conducting MLF in low-pH, cool-climate white musts with potential high alcohol content. [ABSTRACT FROM AUTHOR]

Sulfur dioxide (SO) is probably one of the most versatile and efficient additives used in winemaking due to its antiseptic and antioxidant properties. This compound is also important for minimizing phenolic polymerization rate and color loss during wine aging. However, allergies caused by SO-derived compounds, namely the sulfites, are becoming more frequent, causing symptoms such as headaches, nausea, gastric irritation, and breathing difficulties in asthma patients. Consequently, the legislated maximum concentration of SO allowed in wines has been gradually reduced. For this reason, it is crucial in a competitive global winemaking market strategy, to reduce or even eliminate the use of SO as a preservative and to search for new healthier and safe strategies. This work gives an overview of the main methodologies that have been proposed so far and that have potential to be used in winemaking as an alternative to SO. The addition of compounds such as dimethyl dicarbonate, bacteriocins, phenolic compounds, and lysozyme, and the use of physical methods, namely pulsed electric fields, ultrasound, ultraviolet radiation, and high pressure are discussed and critically evaluated. [ABSTRACT FROM AUTHOR]

This review presents a global view of the current situation of the scientific knowledge about aspects of wine with possible repercussions (positive or negative) on consumer health and wine safety. The presence in wine of some potential harmful compounds such as phytosanitary products, trace metal compounds, sulfites, and some toxics of microbial origin, such as ochratoxin A, ethyl carbamate, and biogenic amines, is discussed. The different strategies and alternative methodologies that are being carried out to reduce or to avoid the presence of these substances in wines are also discussed. In recent years much work has focused on establishing the scientific explanations for the positive biological effects of some wine compounds. In this review, we also examine the latest knowledge regarding wine and health, focusing on two types of compounds that have been related to the positive effects of moderate wine consumption, such as phenolic compounds and bioactive peptides. [ABSTRACT FROM PUBLISHER]